The Effect of Static equilibrium on Strengthening Exercise of Lower Extremity with Unstable Shoes

The purpose of this study is to evaluate the static equilibrium through strengthening exercises of the lower extremity muscles according to the wearing of unstable shoes for six weeks. Thirty female students were included in this study, and they were randomly assigned to the normal shoes group and the unstable shoes group. All participants performed exercise programs such as squats and lunges three times a week for six months. To measure static equilibrium during pre/post tests, the participants performed single-leg stand and collected data on the total COP(center of pressure) path length, speed, area, ratio of Rambling to COP ratio and Trembling to COP ratio, and frequency, elasticity, and stiffness of tibialis anterior and gastrocnemius. The results indicated that there was an interaction between the normal shoes group and the unstable shoes group in terms of the total path length of COP(F=4.092, p=.049). The unstable shoes group decreased during the post-test than the pre-test(p=.010). Rambling and Trembling in the medial-lateral direction showed interactions(Rambling: F=3.858, p=.044, Trembling: F=3.066, p=.035). After training, the unstable shoes group decreased compared to the normal shoes group(Rambling: p=.040, Trembling: p=.008). Also, muscle stiffness of lateral gastrocnemius showed an interaction between the two shoes(F=15.545, p=.000). The stiffness of the unstable shoes group decreased more during the post-test than the pre-test(p=.020), unstable shoes group was decreased than normal shoes(p= .008). Therefore, it was found that there was a high effect on maintaining equilibrium when performing an exercise program to improve lower extremity muscle after wearing unstable shoes.